FNA uses a thin, hollow needle (thinner than the needles used to draw blood) to draw out fluid or tissue from a lump. Depending on the size and location of the lump, the needle is sometimes directed into the lump simply by feeling it. Other times it may be guided into the lump with the assistance of an ultrasound. FNAs are rarely painful and don’t tend to leave scars. Although FNA is the easiest type of biopsy to have, it doesn’t always provide a clear result.